1. Technical Field
This invention relates to sensors and, more particularly, to a device for sensing characteristics of a battery.
2. Discussion
In many applications it would be desirable to sense the characteristics of a battery. This is especially true with batteries that are used to power equipment where it is essential that a reliable source of power is consistently maintained. For example, batteries used on many systems by the Department of Defense are being replaced with the latest technology high-reliability, maintenance-free batteries (HRMFB). While improvements in reliability and performance are expected from these new batteries, reliability engineers need to understand and quantify the actual gains to establish optimum maintenance intervals and number of required spares. Basing these decisions on real-life performance data, as opposed to educated guesses, will yield significant cost savings by reducing the work load on battery maintenance and avoiding having too many or too few spare batteries on the shelves. The devices may also provide a means for determining whether a failed battery was within warranty limits.
It is known that the environment to which the battery is exposed can shorten or prolong expected life. Factors having the greatest effect on battery reliability include operating time, number of charge/discharge cycles, number and severity (i.e. magnitude depth) of deep-discharge cycles, temperature fluctuations, and G-loads. Sensors are currently available to measure and record these parameters, but most of them require costly retrofit or redesign of the battery structure to enable the sensor to be installed. In most cases it is neither practical nor cost effective to hard-wire a sensor inside an aircraft battery. Because of these drawbacks, data on large numbers of batteries under real operating conditions are difficult to obtain.
The present invention is directed to solving one or more of these problems.